Second-hand iPhone XS voicemail asks for pw of previous owner?

Question

How can I change voicemail password? No, I cannot contact the previous owner.

Answer 1

Everything to do with the original owner 

should have been cleared out before you bought the phone. 

Take it to a store that represents your carrier and have it done. 

Answer 2

Factory restore it, I hope previous owner didn't leave icloud account on it, if so you'll be icloud activation locked. I don't know if your using same Sim card from previous owner or your using a new card if that's causing it.